Calotype\SEO\Generators\SitemapGenerator::validateData PHP Method

    protected function validateData($data)
    {
        $data = $this->replaceAttributes($data);
        foreach ($this->required as $required) {
            if (!array_key_exists($required, $data)) {
                $replacement = array_search($required, $this->replacements);
                if ($replacement !== false) {
                    $required = $replacement;
                }
                throw new \InvalidArgumentException("Required sitemap property [{$required}] is not present.");
            }
        }
    }